Receiver and method of recovering data from radio signals

Abstract

A receiver recovers data for at least one of a plurality of users from radio signals generated by the plurality of users. The receiver includes data detectors, each of which is associated with one of a plurality of temporal displacements in communications paths through which the radio signals pass. Each of the data detectors estimates a user data symbol for one of the plurality of users from at least one of the radio signals. The receiver also includes a signal strength estimator to estimate signal strengths of the radio signals, and a receiver controller to assign user codes and the temporal displacements to each the plurality of data detectors according to the signal strengths of the radio signals. The receiver controller assigns a first user code for a first user to a first number of data detectors and a second user code for a second user to a second number of data detectors. The first number of data detectors has different temporal displacements than the second number of data detectors.

1. A receiver for recovering data for at least one of a plurality of users from radio signals associated with the plurality of users, the receiver comprising:
 data detectors, each of the data detectors being associated with one of a plurality of temporal displacements of communications paths through which the radio signals pass, each of the data detectors to estimate a user data symbol for one of the plurality of users from at least one of the radio signals; 
 a signal strength estimator to estimate signal strengths of the radio signals; and 
 a receiver controller to assign user codes and temporal displacements to the data detectors according to the signal strengths of the radio signals, the receiver controller assigning a first user code for a first user to a first number of data detectors and a second user code for a second user to a second number of data detectors, the first number of data detectors having different temporal displacements than the second number of data detectors. 
 
     
     
       2. The receiver of  claim 1 , wherein the first number of data detectors is greater than the second number of data detectors, and wherein a radio signal for the first user has a weaker signal strength than a radio signal for the second user. 
     
     
       3. The receiver of  claim 1 , wherein the first number of data detectors is greater than the second number of data detectors, and wherein a radio signal for the first user has a stronger signal strength than a radio signal for the second user. 
     
     
       4. The receiver of  claim 1 , further comprising:
 a combiner to combine estimated user data symbols for the first user to form a composite symbol. 
 
     
     
       5. The receiver of  claim 4 , further comprising:
 a single processor that includes the combiner and the signal strength estimator, wherein the receiver controller controls the single processor. 
 
     
     
       6. The receiver of  claim 1 , further comprising a data store to store the radio signals, the radio signals being received within a pre-determined time window, wherein the radio signals are input to the data detectors from the data store under control of the receiver controller. 
     
     
       7. The receiver of  claim 1 , wherein the data detectors comprise rake fingers, the user codes comprise spreading codes, and the radio signals are generated in accordance with a code division multiple access (CDMA) process. 
     
     
       8. The receiver of  claim 1 , wherein the signal strength estimator re-estimates signal strengths of the radio signals at the temporal displacements, and the receiver controller re-assigns the user codes and the temporal displacements to the data detectors in accordance with re-estimated signal strengths of the radio signals. 
     
     
       9. The receiver of  claim 1 , further comprising:
 a signal re-generator coupled to the data detectors, the signal re-generator to re-generate a radio signal for the first user by combining an estimated user data symbol for the first user with one of the user codes. 
 
     
     
       10. The receiver of  claim 9 , wherein each of the data detectors comprises:
 subtracting means to subtract a regenerated radio signal from a corresponding radio signal prior to estimating a user data symbol. 
 
     
     
       11. A method of recovering data for at least one of a plurality of users from radio signals associated with the plurality of users, the method comprising:
 assigning, to each of plural data detectors, (i) one of a plurality of user codes, and (ii) one of a plurality of temporal displacements that correspond to communications paths through which the radio signals pass; 
 estimating user data symbols using the data detectors and the radio signals; 
 determining signal strengths of the radio signals; and 
 re-assigning the plurality of user codes and the plurality of temporal displacements to the data detectors; 
 wherein the re-assigning assigns a first user code for a first user to a first number of data detectors and a second user code for a second user to a second number of data detectors, the first number of data detectors having different temporal displacements than the second number of data detectors. 
 
     
     
       12. The method of  claim 11 , wherein the first number of data detectors is greater than the second number of data detectors, and a radio signal for the first user has a weaker signal strength than a radio signal for the second user. 
     
     
       13. The method of  claim 11 , wherein the first number of data detectors is greater than the second number of data detectors, and a radio signal for the first user has a stronger signal strength than a radio signal for the second user. 
     
     
       14. The method of  claim 11 , further comprising combining estimated user data symbols for the first user to form a composite symbol. 
     
     
       15. The method of  claim 11 , further comprising:
 storing the radio signals, the radio signals being received within a pre-determined time window; and 
 re-estimating user data symbols using stored radio signals and data detectors with re-assigned user codes and temporal displacements. 
 
     
     
       16. The method of  claim 15 , further comprising:
 re-determining signal strengths of the stored radio signals; and 
 re-assigning user codes to the data detectors in accordance with signal strengths of the stored radio signals. 
 
     
     
       17. The method of  claim 15 , further comprising:
 re-generating radio signals for the first user, wherein re-generating comprises combining estimated user data symbols with one of the reassigned user codes. 
 
     
     
       18. The method of  claim 17 , further comprising: subtracting the re-generated radio signals from corresponding radio signals prior to re-estimating the user data symbols. 
     
     
       19. The method of  claim 11 , wherein the data detectors comprise rake fingers and the user codes comprise spreading codes. 
     
     
       20. The method of  claim 11 , wherein the radio signals are generated in accordance with a code division multiple access process.